The Rt values are above 1 in all regions. The plots of the Rt over time show a plateauing in most regions in the most recent weeks, with downward trends in the North East and Yorkshire and the North West. These lower values of Rt might be the result of various social distancing interventions, but the impact is not strong enough to reduce the Rt values below 1.
These trends in the values for Rt and the number of new infections over time have recently been interrupted by the school half-term period, the impact of which is reflected in our model through inclusion of Department for Education attendance and Google mobility data.
After this period, the values of Rt revert to their pre-half-term levels. As Rt remains above 1, the number of new infections occurring each day will continue to rise.
The lock-down introduced on the 5th of November will have induced changes in contact patterns that are not yet possible to quantify. These may influence the estimation of Rt in the near future, which will be reflected in the weekly iterations of our model.
Real-time tracking of an epidemic, as data accumulate over time, is an essential component of a public health response to a new outbreak. A team of statistical modellers at the MRC Biostatistics Unit (BSU), University of Cambridge, are working to provide regular now-casts and forecasts of COVID-19 infections and deaths. This information feeds directly to the SAGE sub-group, Scientific Pandemic Influenza sub-group on Modelling (SPI-M), and to regional Public Health England (PHE) teams.
We fit a transmission model (Birrell et al. 2020) to a number of data sources (see ‘Data Sources’), to reconstruct the number of new COVID-19 infections over time in different age groups and NHS regions, estimate a measure of ongoing transmission and predict the number of new COVID-19 deaths.
We use:
Data are stratified into eight age groups: <1, 1-4, 5-14, 15-24, 25-44, 45-64, 65-74, 75+, and the NHS England regions (North East and Yorkshire, North West, Midlands, East of England, London, South East, South West).
Value of \(R_t\), the average number of secondary infections due to a typical infection today.
The percentage of a given group that has been infected.
NB: negative growth rates are rates of decline. Values are daily changes.
| Region | Median | 95% CrI (lower) | 95% CrI (upper) |
|---|---|---|---|
| England | 0.05 | 0.04 | 0.06 |
| East of England | 0.06 | 0.03 | 0.09 |
| London | 0.04 | 0.01 | 0.07 |
| Midlands | 0.06 | 0.04 | 0.08 |
| North East and Yorkshire | 0.02 | 0.00 | 0.04 |
| North West | 0.02 | 0.00 | 0.03 |
| South East | 0.07 | 0.04 | 0.10 |
| South West | 0.07 | 0.04 | 0.10 |
Halving times in days, if a region shows growth than value will be NA.
| Region | Median | 95% CrI (lower) | 95% CrI (upper) |
|---|---|---|---|
| England | NA | NA | NA |
| East of England | NA | NA | NA |
| London | NA | NA | NA |
| Midlands | NA | NA | NA |
| North East and Yorkshire | NA | NA | NA |
| North West | NA | 1864.64 | NA |
| South East | NA | NA | NA |
| South West | NA | NA | NA |
Doubling times in days, if a region shows decline then the value will be NA.
| Region | Median | 95% CrI (lower) | 95% CrI (upper) |
|---|---|---|---|
| England | 14.04 | 11.29 | 18.18 |
| East of England | 11.25 | 7.71 | 22.68 |
| London | 17.31 | 9.97 | 137.12 |
| Midlands | 11.18 | 8.67 | 16.64 |
| North East and Yorkshire | 29.91 | 16.25 | 383.56 |
| North West | 38.76 | 20.19 | NA |
| South East | 9.44 | 6.86 | 17.16 |
| South West | 9.51 | 6.66 | 17.68 |
NB: negative growth rates are rates of decline. Values are daily changes.
| Region | Median | 95% CrI (lower) | 95% CrI (upper) |
|---|---|---|---|
| England | 0.02 | 0.02 | 0.03 |
| East of England | 0.04 | 0.01 | 0.06 |
| London | 0.02 | -0.01 | 0.04 |
| Midlands | 0.04 | 0.02 | 0.06 |
| North East and Yorkshire | 0.01 | -0.01 | 0.02 |
| North West | 0.01 | -0.01 | 0.02 |
| South East | 0.05 | 0.02 | 0.07 |
| South West | 0.05 | 0.02 | 0.08 |
Halving times in days, if a region shows growth than value will be NA.
| Region | Median | 95% CrI (lower) | 95% CrI (upper) |
|---|---|---|---|
| England | NA | NA | NA |
| East of England | NA | NA | NA |
| London | NA | 70.53 | NA |
| Midlands | NA | NA | NA |
| North East and Yorkshire | NA | 96.07 | NA |
| North West | NA | 106.73 | NA |
| South East | NA | NA | NA |
| South West | NA | NA | NA |
Doubling times in days, if a region shows decline then the value will be NA.
| Region | Median | 95% CrI (lower) | 95% CrI (upper) |
|---|---|---|---|
| England | 28.61 | 21.66 | 42.95 |
| East of England | 18.98 | 11.19 | 62.57 |
| London | 40.93 | 16.18 | NA |
| Midlands | 17.01 | 11.89 | 30.12 |
| North East and Yorkshire | 81.93 | 28.56 | NA |
| North West | 94.60 | 32.93 | NA |
| South East | 15.13 | 9.78 | 37.68 |
| South West | 14.54 | 9.06 | 35.99 |
The blue lines is show when interventions have been introduced (lockdown on 23 Mar and the relaxation of measures on 11 May), and the red line shows the date these results were produced (08 Nov).
The figure below shows the probability that \(R_t\) is greater than 1 (ie: the number of infections is growing) in each region over time. Clicking the regions in the legend allows lines to be added or removed from the figure.
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